1. Field of the Invention
The present invention relates generally to the detection and treatment of viral infection. More particularly, the invention relates to compositions and methods useful for the diagnosis of and vaccination against infection with a newly-discovered family of lymphotropic viruses designated activating virus (AV).
2. Description of Related Art
Viruses can contribute to the development of human tumors by a variety of mechanisms ranging from genetic stimulation of proliferation in host cells to induced immunosuppression that permits emergence of tumors not directly related to the suppressing virus. For instance, a patient infected with human immunodeficiency virus (HIV) has substantially increased risk for developing Kaposi sarcomas and B cell lymphomas, apparently due to immunosuppression caused by the HIV infection. Herpes simplex virus (HSV), on the other hand, has been suspected of contributing to tumors, particularly anogenital and oral cancers (A. Nahmias, et al., Am. J. Epidemol., 91:547, 1970; W. E. Rawls, et al., Cancer Res., 33:1542, 1973; R. Duff, et al., J. Virol., 8:469, 1971; H. zur Hausen, Int. Rev. Exp. Pathol, 25:307, 1983).
Epstein-Barr virus (EBV), hepatitis B virus, several types of papilloma viruses, and HTLV-I and possibly II (human T-cell leukemia-lymphoma virus) are consistently linked to specific malignancies, but none of these viruses has been shown to be sufficient alone to induce cancer. Recent studies suggest that the Epstein-Barr and human papilloma viruses carry genes that immortalize infected cells and cause them to divide continuously. Evidence points to two genes, designated E6 and E7, as the likely transforming genes of the cancer-associated papilloma viruses. Both genes are consistently found in the DNA of cervical cancer cells, for example, and are active there. The Epstein-Barr virus also appears to carry a transforming gene, EBNA-2, that may stimulate the expression of other viral and cellular genes, including the latent membrane protein gene. Hepatitus B virus does not carry transforming genes so far as is known, yet it leads to liver cancer, perhaps because the viral DNA inserts itself into the genome of infected cells, activating a cellular oncogene.
Despite their significance, no DNA tumor virus can cause cancer by itself. Other changes and causative factors presently unidentified, perhaps several, are also required in infected cells. The present invention discloses a newly discovered virus called the "Activating Virus" or AV. This virus is implicated as a causative factor in a variety of cancers. It has been isolated from a wide variety of cancerous cells, many of which cancers have heretofore been thought to be linked to viral infection as an instigating factor, but where no viral etiologic agent has been found.